Film spool switch



Oct 12, 1948- H. 1 sTRlcKLAND 2,451,256

FILM sPooL SWITCH enf Patented Oct. 12, 1948 UNITED STATES PATENT GFFICE FILM SPOOL SWITCH Howard L. Strickland, Clinton, S. C. Application March '12, 1947, Serial No. '734,076

(Cl. 20D- 52) 2 Claims. 1

My invention relates to improvements in automatic signaling devices for motion picture prolectors.

In the showing of feature length motion pictures it is usual to employ two projectors, each being adapted to show a portion of the nlm. One projector is rst used, and when the portion of the film on its reels has been shown the second projector is brought into use to complete the showing of the motion picture. To assure continuity in the picture during the change over to the second projector, some signaling means is employed to notify the projector` operator that the time for the change over has arrived. This signaling has been accomplished in various ways, and it is a primary lobject `of this invention to provide improved means to signal the operator of motion picture projectors, when it is necessary for him to start up the second projector and change over to the same during a lengthy nlm.

A further important object of the invention is to provide a signaling device for motion picture projectors the operation of which is controlled by the motion picture film, and which has novel means to eliminate the nre hazard due to the inflammability of the nlm.

A further object is to provide a signaling device to warn the projector operator at desired intervals before the end of one lm reel that such end is approaching, and also to instantly alert the operator if the lm should happen to break.

A furtherobject is to provide a device of the above mentioned character, which is simple, compact, durable, and relatively inexpensive to manu*- facture.

Other objects and advantages of the invention will be apparent during the course of the follow*- ing description.

In the accompanying drawings, forming a part of this application, and in which like numerals are employed to designate like parts throughout the same,

Figure l is a horizontal section through a casing' and circuit closing means taken on line I-I of Figure 2,

Figure 2 is a vertical section taken on line 2-2 of Figure 1,

Figure 3 is an electrical wiring schematic of the circuit employed in the use 'of the signaling device,

Figure 4 is a vertical section taken on line 4 4 of Figure 1 showing the nlm and nlm spool,

Figure 5 is a fragmentary vertical section taken on line 5 5 of Figure 1, and,

Figure 6 is a side elevation of a terminal lead and slip ring.

In the drawings, where for the purpose of illustration is shown a preferred embodiment of my invention, the numeral IIJ designates a rectangular casing or housing for circuit closing means.

This housing It! may be formed of metal, such as cast iron or the like, and it comprises a flat rectagnular bottom II, top I2, sides I3, I4, and I5, and a hinged door or cover IE. The casing bottom Il, top I2, and sides I3, III, and I5, are permanently rigidly secured together, forming a unitary structure. The door It is provided with hinges I l, by means of which the door is conm nected to the side I3 of the housing. The door is provided upon its outer side with a knob or handle I8, and upon its inner side adjacent to the side I5, with a suitable resilient latch element I9. The latch element I9 is adapted to engage over a latch boss or shoulder 2), formed upon the inner surface of the side i5, to maintain the swinging door I6 in the closed position. The door may be pulled open by the knob I8 to provide access to the interior of the casing.

Centrally arranged upon the inner surface of the side I4 is a shaft mounting block 2|, having a screw threaded stud 22 formed integral therewith, and extending through an opening 23 in the side I4. A screw threaded nut 2l! engages over the stud 23, to rigidly secure the shaft mounting block 2| tothe side Ill. The block 2| has an axial cylindrical recess 25 in its inner end, and this recess receives one end of a stationary shaft 26. The shaft 26 is rigidly secured within the recess 25 by means of a set screw 2l, engaging in a radial screw threaded opening in the shaft mountnig block 2|. The shaft 2S is formed of suitable electrical insulating material, and it is rigid.

Mounted upon the shaft 25 near its inner at tached end, is an annular adjusting collar 23, provided with a radial set screw 29, by means of which the collar may be securely clamped in the selected adjusted position upon the shaft 26. Also mounted upon the shaft 25 and disposed outwardly from the collar 28 is a suitable coil compression spring 3B. The inner end of this spring 3!) engages against the annular vcollar 25, and the outer end of the spring engages against a contact roller 3| which is rotatably mounted upon the shaft 26, and adapted to slide axially thereon under the influence of spring 38. The contact roller 3| is formed of metal having good electrical conductivity, and it includes an elongated cylindrical tubular hub or contact member 32 having an end 32 and receiving the shaft 2t. The roller 3| also includes a cylindrical spool or drum porN tion 33, the outer periphery of which engages a motion picture iilm Sil, as the same passes vertically through the casing Ill. The motion picture nlm 34 is provided with one or more elongated notches 35, which are formed in the longitudinal edge of the film adjacent to the roller 3|. The rollei` 3| also includes an annular flange or shoulder 35 to engage the longitudinal edge of the film 34 having the notch or notches 35. The roll'cr 3| further includes a small axial extension 3 or hub 31, formed integral therewith, and having an annular groove 39 for a purpose to be described. Rotatably mounted upon the shaft 26, outwardly from the roller 3| is a contact or spark shield roller 46. The roller y4|] is made of metal having good electrical conductivity, and it includes an annular hub portion 4|, having an elongated cylindrical tubular extension or spark shield 42, providing a, cylindrical recess 43 to receive the hub 32 therein, and a contact shoulder 63. A substantial annular space exists between the hub 32 and spark shield 42. Outer end 32 of the hub 32 is adapted to engage and make electrical Contact with the contact shoulder 43' when the roller 3| moves axially outwardly upon the shaft 26. The roller 4|] also includes an annular drum portion 44, of the same diameter as the motor 62 is connected to the wire 68.

drum portion 33, and an annular flange or shoulder 45, identical with the shoulder 36 of the roller 3|. The drum portion 44 and flange 45 are engaged by the motion picture film 34 as the film passes vertically through the casing I6. The roller 4|] further includes a small annular extension 46, formed integral therewith, provided with an annular groove 46. It is thus seen that the contact rollers 3| and 46 constitute a spool or drum over which the lm 34 passes as it moves vertically through the casing I6. Mounted upon the shaft 26, near its outer unsupported end is an annular adjusting collar 49, provided with a set screw 56, for rigidly adjustably clamping the collar upon the shaft 26. Collar 49 is adapted to engage the outer end of the contact roller 4i), to prevent outward axial movement of the roller.

The arrangement of the parts which are mounted upon the shaft 26 is such that the contact rollers 3| and 40 are disposed centrally within the casing I6. The bottom and top I2 of the casing are provided with elongated slots 5| and 52 respectively, to permit the vertical passage of motion picture film 34, and these slots are therefore arranged in alignment with the shaft 26.

Rigidly mounted upon the bottom l| adjacent to the side i3 is a terminal block 53, formed of suitable insulating material The block 53 carries conducting terminal strips 54, rigidly secured thereto. The numeral 55 designates leads or wires having circularly curved U-shaped conducting or slip rings 56 attached to one of their ends, and standard terminal lugs 51 attached to their opposite ends.

The U-shaped slip rings are adapted to snap over the extensions 31 and 46 of the contact rollers, and to be arranged slidably within the annular grooves 39 and 48 for making electrical contact with the rollers. The terminal lugs 51 are secured to the opposite terminal strips 54, as shown in Figure 2. A small opening 56 is provided in the side |3 as a passage for electric wires 59 and 68, which are electrically connected to opposite terminal strips 5,4. The wires 59 and 66 pass out of the casing l0 to connect the contact rollers 3| and 49 of the circuit closing means into the electrical circuit of the motion picture projector.

In Figure 3, a wiring schematic is shown, in4

which two motion picture projectors driven by electric motors 6| and 62 are employed. The numerals 63 and 64 designate the wires of an alternating current supply line to the projector motors. The projector motors 6| and 62 include in their circuits motor switches 65 and 66, electrically connected in wires 61 and 68 respectively. The wire 63 is connected with the wires 61 and 68 at the point 69. The wire 61 is electrically In Figure 3, each motion picture projector is equipped with the -circuit closing means, including the contact rollers 3| and 46, and their associated circuits Each contact roller 46 is electrically connected by the wire 59 with one terminal 11 of the low voltage coil of a transformer 18. The opposite terminals 19 of the low voltage coils are connected by means of wires 69 with one terminal 8| of a signal bell 32. Manually operated normally closed switches 63 are interposed in the wires 8|), between the bell 82 and transformers 18. The Contact rollers 3| are electrically connected with the opposite terminal 84 of the bell 62 by means of wires 66. The terminals 86 of the high voltage coils of transformers 18 are connected with the wires 12 and 16 at the points 81, through wires 68. The opposite terminals 89 of, the high voltage coils are connected with the wires 61 and 66 at points 66, through Wires 9|.

The use and operation of the automatic signaling device is as follows:

Each of the motion picture projectors is equipped with the casing |6, containing the circuit closing means described above. The casing |0 is mounted upon the projector in any suitable manner, and is disposed between the film reels of such projector. The arrangement is such that the lm being run off one projector reel and onto the other reel passes vertically through the aligned slots 5| and 52 of the casing I6.

Referring to Figure 3, the projector motor switch 66 is opened, so that its associated projector will not operate. The switch 65 is closed, and the projector driven by the motor 6| will operate. Current ows through wire 63, wire 61, motor switch 65, through the stator Winding of the motor 6|, wire 12, and back to the wire 64. At this time the lm upon the .projector reels is passing over the spool consisting of the contact rollers 3| and 46 within the associated casing |6. The parallel longitudinal edges of the moving lm engages the annular flanges 36 and 45 of the rollers, and maintain the rollers separated and axially spaced from each other upon the stationary shaft 26, see Figures 1 and 2. The film is under sufficient tension at all times to enable it to counteract the force of spring 36, which tends at all times to push the roller 3| into engagement with the roller 46.

At the desired point or points on the film, and somewhere near the end of the same, the longitudinal elongated notches 35 are provi-ded. The notch or notches 35 are preferably about onesixteenth of an inch in depth and approximately three inches long. It is desirable to locate one of these notches about one-hundred and fty feet from the end of the lm on the first projector, to provide a preliminary signal so that the operator will at that time light the projector lamp of the opposite machine. A second notch may be provided about sixteen feet from the end of the lm to provide a signal for the operator to start the motor of the second projector. A third notch is preferably located about four feet from the end of the film to signal the operator for the actual change over to the opposite projector for the showing of the rest of the movie.

When each of the above described notches 35 passes through the casing l0 and over the associated spool, such notch will become adjacent to the ilange 36 of the con-tact roller El, When this occurs, the spring 30 will cause the roller 3! to shift axially outwardly upon the shaft 2S, and the outer end 32 will make electrical contact with the contact shoulder 43 of the roller 19. When this occurs current ows through the wire 0S, terminals 36 and 89 of the high voltage coil of transformer '18, and through the wire Si, back to the wire 61. Simultaneously, current will be induced in the low voltage winding of transformer 78, and it will flow through the wire 59, lead 55, contact rollers 46 and 3|, the other lead 55, wire 60, through the terminals 84 and 8i of the signal bell 82, and through the wire Si?, back to the transformer terminal '19. The signal bell B2 will ring at that instant, to notify the operator, as stated.

When the end of the lm on the reels of the first projector has been reached, and the second projector having the motor `62 is started, the motor switch 66 is closed, and the switch 65 of the rst projector is opened. If it becomes necessary to switch back to the first projector again before running the third reel of a long motion picture, the circuit closing means associated with the second projector will operate in the same manner as described in connection with the first projector.

The manually operated switches 83 are provided in case it is desirable not to use the signaling device, in which case these switches may be opened. The switches 83 are closed while the device is in use.

Particular attention is called to the construction of the spool consisting of the contact rollers 3l and 46. These rollers are designed to eliminate entirely the re hazard caused by sparks, made possible when the rollers 3! and, 40 make electrical contact in close proximity to the inammable film. The shield 42 of the roller 40 completely protects the film from the possibility of contact with such flying sparks.

It is to =be .understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to, without departing from the spirit of my invention or the scope of the sub'joined claims.

Having thus described my invention, what I claim is:

1. An electrical circuit closing switch for use in connection with a lm having a notch in its longitudinal edge, said switch comprising a rotatable spool, said spool including electrical con-- ducting axially arranged rollers ha ing flanges at ltheir outer ends, the film being arranged between the flanges, said rollers including inner and outer sleeves disposed axiaily inwardly of the flanges and telescoping, the sleeves being radially insulated, the free end of the inner sleeve engaging the companion roller at the closed end of the outer sleeve for `closing the circuit, a spring to effect a relative axial movement between the rollers when the flange of one roller enters the notch in the film, and elements having permanent electrical contact with the rollers.

2. An electrical circuit closing switch for use in connection with a lm having a notch in its longitudinal edge,A said switch comprising a shaft formed of insulating material, a rotatable spool mounted upon said shaft, and spool including electrical conducting axially arranged rollers having flanges at their outer ends, the ilm being arranged between the flanges, said rollers including inner and outer sleeves disposed axially inwardly of the flanges and telescoping, the sleeves being radially insulated, the free end of the inner sleeve engaging the companion roller at the closed end of the outer sleeve for closing the circuit, a spring to effect a relative axial movement between the rollers when the lange of one roller enters the notch in the nlm, and elements having permanent electrical contact with the rollers HOWARD L. STRICKLAND.

REFERENCES CITED rlhe following references are of record in the le of this patent:

UNTED STATES PATENTS Number Name Date 1,476,006 Phimistei Dec. 4, 1923 1,718,387 Simons June 25, 1929 1,821,775 Tittle Sept, 1, 1931 2,016,506 Maluss et al. Oct. 8, 1935 FOREIGN PATENTS Number Country Date 599,001 Germany June 22, 1934 

